The soil microbe Bacillus thuringiensis (B.t.) is a Gram-positive, spore-forming bacterium traditionally characterized by parasporal crystalline protein inclusions. These inclusions often appear microscopically as distinctively shaped crystals. The proteins can be highly toxic to pests and specific in their toxic activity. Certain B.t. toxin genes have been isolated and sequenced, and recombinant DNA-based B.t. products have been produced and approved for use. In addition, with the use of genetic engineering techniques, new approaches for delivering B.t. toxins to agricultural environments are under development, including the use of plants genetically engineered with endotoxin genes for insect resistance and the use of stabilized intact microbial cells as B. t. toxin delivery vehicles (Gaertner, F. H., L. Kim [1988] TIBTECH 6:S4-S7; Beegle, C. C., T. Yamamoto, "History of Bacillus thuringiensis Berliner research and development," Can. Ent. 124:587-616). Thus, isolated B.t. toxin genes are becoming commercially valuable.
Until the last fifteen years, commercial use of B.t. pesticides has been largely restricted to a narroa range of lepidopteran (caterpillar) pests. Preparations of the spores and crystals of B. thuringiensis subsp. kurstaki have been used for many years as commercial insecticides for lepidopteran pests. For example, B. thuringiensis var. kurstaki HD-1 produces a crystalline .delta.-endotoxin which is toxic to the larvae of a number of lepidopteran insects.
Investigators, have now discovered B.t. pesticides with specificities for a much broader range of pests. For example, other species of B.t., namely israelensis and morrisoni (a.k.a. tenebrionis, a.k.a. B.t. M-7, a.k.a. B.t. san diego), have been used commercially to control insects of the orders Diptera and Coleoptera, respectively (Gaertner, F. H. [1989] "Cellular Delivery Systems for Insecticidal Proteins: Living and Non-Living Microorganisms," in Controlled Delivery of Crop Protection Agents, R. M. Wilkins, ed., Taylor and Francis, New York and London, 1990, pp. 245-255.). See also Couch, T. L. (1980) "Mosquito Pathogenicity of Bacillus thuringiensis var. israelensis," Developments in Industrial Microbiology 22:61-76; and Beegle, C. C. (1978) "Use of Entomogenous Bacteria in Agroecosystems," Developments in Industrial Microbiology 20:97-104. Krieg, A., A. M. Huger, G. A. Langenbruch, W. Schnetter (1983) Z. ang. Ent. 96:500-508 describe Bacillus thuringiensis var. tenebrionis, which is reportedly active against two beetles in the order Coleoptera. These art the Colorado potato beetle, Leptinotarsa decemlineata, and Agelastica alni.
More recently, new subspecies of B.t. have been identified, and genes responsible for active .delta.-endotoxin proteins have been isolated (Hofte, H., H. R. Whiteley [1989] Microbiological Reviews 52(2):242-255). Hofte and Whiteley classified B. t. crystal protein genes into four major classes. The classes were CryI (Lepidoptera-specific), CryII (Lepidoptera- and Diptera-specific), CryIII (Coleoptera-specific), and CryIV (Diptera-specific). The discovery of strains specifically toxic to other pests has been reported (Feitelson, J. S., J. Payne, L. Kim [1992] Bio/Technology 10:271-275). CryV has been proposed to designate a class of toxin genes that are nematode-specific. Lambert et al. (Lambert, B., L. Buysse, C. Decock, S. Jansens, C. Piens, B. Saey, J. Seurinck, K. van Audenhove, J. Van Rie, A. Van Vliet, M. Peferoen [1996] Appl. Environ. Microbiol 62(1):80-86) describe the characterization of a Cry9 toxin active against lepidopterans. Published PCT applications WO 94/05771 and WO 94/24264 also describe B.t. isolates active against lepidcpteran pests. Gleave et al. ([1991] JGM 138:55-62), Shevelev et al. ([1993] FEBS Lett. 336:79-82; and Smulevitch et al. ([1991] FEBS Lett. 293:25-26) also describe B.t. toxins. Many other classes of B.t. genes have now been identified.
The cloning and expression of a B.t. crystal protein gene in Escherichia coli has been described in the published literature (Schnepf, H. E., H. R. Whiteley [1981] Proc. Natl. Acad. Sci. USA 78:2893-2897.). U.S. Pat. No. 4,448,885 and U.S. Pat. No. 4,467,036 both disclose the expression of B.t. crystal protein in E. coli. U.S. Pat. Nos. 4,990,332; 5,039,523; 5,126,133; 5,164,180; and 5,169,629 are among those which disclose B.t. toxins having activity against lepidopterans. PCT application WO96/05314 discloses PS86W1, PS86V1, and other B.t. isolates active against lepidopteran pests. The PCT patent applications published as WO94/24264 and WO94/05771 describe B.t. isolates and toxins active against lepidopteran pests. B.t. proteins with activity against members of the family Noctuidae are described by Lambert et al., supr2. U.S. Pat. Nos. 4,797,276 and 4,853,331 disclose B. thuringiensis strain tenebrionis which can be used to control coleopteran pests in various environments. U.S. Pat. No. 4,918,006 discloses B.t. toxins having activity against dipterans. U.S. Pat. No. 5,151,363 and U.S. Pat. No. 4,948,734 disclose certain isolates of B.t. which have activity against nematodes. Other U.S. Pat. Nos. which disclose activity against nematodes include 5,093,120; 5,236,843; 5,262,399; 5,270,448; 5,281,530; 5,322,932; 5,350,577; 5,426,049; and 5,439,881.
A cry2Aa gene from HD263 kurstaki is disclosed by Donovan et al. in 264 JBC 4740 (1989). Another cry2Aa gene and a cry2Ab gene, from HD1 kurstaki, are disclosed by Widner & Whiteley, 171 J Bac. 965-974 (1989). Another cry2Ab gene from HD1 kurstaki is disclosed by Dankocsik et al. in 4 Mol. Micro 2087-2094 (1990). A cry2Ac gene from B. t. S-1 (shanghai) is disclosed by Wu et al. in 81 FEMS 31-36 (1991).
An isolate known as PS192M4 is disclosed in U.S. Pat. No. 5,273,746 as having activity against lice.
The PS86I2 isolate is disclosed in U.S. Pat. No. 5,686,069 as having activity against lepidopterans. PS91C2 is exemplified therein as producing a CryIF(b)-type of lepidopteran-active toxin, the sequence of which is disclosed therein.
Sequence in formation for a lepidopteran-active toxin from HD525 and the sequence of a lepidopteran-active toxin from HD573 are disclosed in WO 98/00546. Those toxins are not Cry2-type toxins.
As a result of extensive research and investment of resources, other patents have issued for new B.t. isolates and new uses of B.t. isolates. See Feitelson et al., supra, for a review. However, the discovery of new B.t. isolates and new uses of known B.t. isolates remains an empirical, unpredictable art. U.S. Pat. No. 5,506,099 describes methods for identifying unknown B.t. isolates. U.S. Pat. No. 5,204,237 describes specific and universal probes for the isolation of B.t. toxin genes. These patents, however, do not describe the probes and primers of the subject invention.